In STAR (Social Science Training and Research) II, Columbia University faculty and Vietnamese investigators will collaborate to build the capacity of the Vietnamese social science research community and to support Hanoi Medical University (HMU) as the emerging national hub for the production and dissemination of social and behavioral science knowledge related to HIV and AIDS. Building on the national center of excellence in social science approaches to HIV prevention, treatment and care established in STAR I, our proposed collaboration includes an infrastructure core, three pilot research projects, and a multi- level dissemination strategy. Infrastructure core activities at HMU will: create a comprehensive IT platform for research through a portal for on-line proposal development and IRB review; provide training in funding mechanisms and the craft of grant-writing; build capacity in theoretically-grounded interdisciplinary social science and HIV research, including developing a Health Data Repository to enhance access to and analytic work on population-level data sets; and implement critical changes to improve the scientific and administrative processes of the Journal of Medical Research, Vietnam's flagship venue for biomedical and health sciences research. Ethics figure prominently in the planned infrastructure core activities, with an innovative plan to collaborate with the Collaborative Institutional Training Initiative (CITI at University of Miami) and Fogarty-funded AIDS training programs to support the translation of CITI's existing on-line research ethics training program into Vietnamese and to add to that program by contributing modules in public health ethics; the on-line, contextually-adapted, Vietnamese-language ethics training program will then be available to research teams and investigators throughout Vietnam. Pilot research projects will generate evidence and build capacity in three areas vital for Vietnam's response to HIV/AIDS: theory-based HIV prevention with MSM; engagement with ART care among IDUs with AIDS, and the sustainability and country-ownership of Vietnam's scaled-up prevention and care programs, which face an uncertain future with the looming withdrawal of PEPFAR. The complementary Dissemination and Network building strategy, carried out in collaboration with the Vietnam Public Health Association (VPHA), involves founding a social science, health and HIV section within VPHA, linked to a broad Knowledge Network on HIV/AIDS, Social Science, and Public Health (VKN). The VKN will build intellectual community for social scientists, create spaces for interchange between scientists and policy makers, produce Vietnamese-language HIV Research Briefs, and support the engagement of Vietnamese social scientists with those on the cutting edge of these issues in the global South. Working in collaboration with major regional Vietnamese health research institutions, key Vietnamese policymaking bodies, and other US government funded HIV/AIDS initiatives, STAR II will provide vital tools to support Vietnam's transition to a nation able to produce the evidence needed for sound and effective HIV prevention and care policies.